#include <bits/stdc++.h>
using namespace std;
#define ll long long
ll ans, sx, sy, n;

int main()
{
	int n;
	cin >> n;

	for (int i = 0; i < n; ++i)
	{
		int x, y;
		cin >> x >> y;
		ans += (n - 1) * (x * x + y * y) - ((x * sx + y * sy) * 2);
		sx += x, sy += y;
	}
	cout << ans;
	return 0;
}